This invention relates generally to a sharpening tool for sharpening knives and other blades.
To optimize cutting performance, blades must be maintained in a sharpened state. Sharpening of a blade during the manufacturing thereof is typically performed using powered abrasive belts or wheels and with specific fixtures which present the blade at the correct angle for sharpening. Accordingly, when the user purchases the blade, whether it is in a knife, pair of scissors, or lawnmower blade, etc., the blade is sharp and ready for use.
However, as the blade is put into use and encounters abrasive surfaces in the materials being cut, the blade eventually loses its sharpness, thereby reducing the blade's cutting effectiveness. This requires the user to again sharpen the blade to restore the original sharp edge.
Since sharpening can be a time consuming, tedious process, the user may avoid it. Sharpening of the blade may also be neglected by the user because of a hesitancy in their ability to actually bring a sharp edge to the blade. Accordingly, once the blade has been put into use and is dulled, it often times is not re-sharpened, thereby reducing the value of the blade as an effective tool.
Various devices have been patented for sharpening blades. U.S. Pat. No. 1,595,322, issued to Tanner, discloses a sharpening device having two rotatable sharpening discs connected to a handle. U.S. Pat. No. 2,446,909, issued to Davis, discloses a knife sharpener having three beveled sharpening discs. The discs, in combination, provide two sharpening interfaces to allow for both a rough and finishing sharpening of a blade. U.S. Pat. No. 2,520,279, issued to Gallo, discloses a device having three discs in series, the central disc being hardened about its periphery. U.S. Pat. No. 4,558,540, issued to the present applicant, discloses a knife sharpener having a tray which holds a sharpening element. A push button is provided for locking the tray with respect to a handle.
While the foregoing designs are known, there still exists a need for a compact and easy to use sharpener which requires little or no skill to operate and which presents a blade to sharpening media at a proper angle for sharpening.